Uploading large files fail with upload infusion

In our php-fusion site we installed the Advanced Upload Infusion and after some trouble got it to work correctly, but only from files < 10MB. I asked my provider and got some tips:
1. I created a .htaccess file in the php-file directory and entered the line:

php_value max_file_upload 50M

2. In the advanced_file_uploads_admin.php file:

// Settings
if (ini_get('upload_max_filesize') != 0) {
$upload_maxsize = str_replace("M","", ini_get('upload_max_filesize'))*1024*1024;
} else {
$upload_maxsize = 50097152;
}

But still I cannot upload larger files. Who can help me further? Thanks for your reply.